Now, the company has a new video showing how it's using sea water
to cool its new data center in Hamina, Finland. The water is
sucked in through granite tunnels -- the site used to be a paper
mill, so the tunnels were already there. Google says it used a
tiny submarine to make sure the tunnels weren't blocked.

Then it's pumped through the data center in pipes, and run into
exchangers that dissipate the heat from servers. Then it's mixed
back with cooler water and put back into the sea.

There's no air conditioning or other cooling system.

This is a simple money-saver. Typically, energy is the biggest
expense at a big data center -- it costs far more than the
building and the hardware and wiring in it -- and historically
air conditioning was a big part of that bill. Facebook's
new data center in Oregon uses air cooling, but this is the
first one we've heard of that's cooled with ocean water.